Such a gripper is e.g. known from European patent application 368 777. This gripper has a pneumatic drive enabling the gripping arms to be moved. The pneumatic drive comprises rods, a pneumatic cylinder and a compressed air source connected thereto by means of valves.
The disadvantage of such a gripper is that it comprises several components which cooperate with one another. Therefore the gripper is heavy, expensive and requires complicated maintenance, because it is constantly necessary to ensure an adequate lubrication of the joints and that the important gaps are kept clean.